JPS5927353Y2 - Hull resistance reduction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for reducing the resistance experienced by a ship during navigation, and particularly to a device for reducing resistance to a ship's hull suitable for use in high-speed ships.

There are conventional resistance reducing devices as shown in Figures 1 and 2, where Figure 1 is a side view and Figure 2 is a side view of Figure 1.
FIG. 3 is a cross-sectional view taken along line 1, and FIG. 3 is a plan view showing a state in which a ship equipped with the above device is turning.

4 is an enlarged side view showing the vicinity of the stern end of the vessel, and FIG. 5 is a sectional view taken along the line ■-■ in FIG. 4.

In Figs. 1 to 5, 1 is the main hull, 2 is the rudder, 3 is the propeller, 4 is the stern bossing, 5 is the propeller shaft, 6 is the propeller cap, 7 is the upper rudder support member, 8 is the rudder stem, 9
9a and 9a are the outer plates of the protrusion 9, 9b and 9b are reinforcing members of the protrusion 9, 10 is the load waterline, 10a is an arbitrary waterline, 10b is the water surface during navigation, 1
1 is the rear end of the main hull above the load waterline, 11' is the rear end of the main hull below the water surface, 12 is the hull centerline, 13 is the turning trajectory of the ship, 14 is the water flow at the stern, 15a is the upper stern frame, 15b are lower stan frames, 16a, 16b
is the turbulence of the water flow, l is the amount of protrusion, 0 is the center point of the ship, and p is the turning center of the ship.

As shown in FIGS. 1 and 2, a protrusion 9 is provided behind the rear end 11 of the main hull 1 above the load waterline 10, with a part of the protrusion 9 positioned above the load waterline 10, and the rest of the protrusion 9 positioned above the load waterline 10. It is known that by locating it below 10, waves generated from the stern of the main hull 1 and waves generated from the protrusion 9 can interfere with each other, thereby reducing hull resistance.

However, if the protrusion 9 as a wave-dissipating object is made to protrude further rearward than the rear end 11 of the main hull 1 by a protrusion amount l, not only will this cause problems during berthing and unberthing work, but also waves will Collision with the object 9 generates excessive stress at the connection part with the main hull 1, which may cause damage.

Furthermore, as shown in FIG. 3, when the ship turns, the water flow 14 at the stern that flows outside the turning amount collides with the protrusion 9, which similarly causes an excessive force on the connection with the main hull 1. It has the disadvantage of creating stress that can cause damage.

Furthermore, general ships do not always sail only at the loaded waterline 10, and the waterline changes depending on the loading situation, so the buoyancy of the protrusion 9 changes due to such changes in the waterline, and the weight of the protrusion 9 changes. If the buoyancy becomes too large compared to the buoyancy, there is a problem in that excessive stress is generated at the connection between the protrusion 9 and the main hull 1.

Furthermore, as a result of providing the protrusion 9 behind the rudder 2 that has the effect of blocking the water flow 14 at the stern when turning, the directional stability of the ship becomes excessive, resulting in a decrease in maneuverability (deterioration of rudder effectiveness). This has led to the problem that it becomes difficult for the ship to turn even when the ship is steered.

On the other hand, the connecting portion between the main hull 1 and the protrusion 9 is usually not fluid-dynamically smooth enough to cause disturbances in the water flow.

That is, as shown in Figs.
Disturbances in water flow as shown by 6a and 16b are likely to occur.

Therefore, it is important to minimize, and if possible eliminate, this turbulence in the water flow in order to increase the effectiveness of the hull resistance reducing device.

Based on these points of view, the present invention reduces the turbulence of water flow near the connection between the protrusion and the main hull, and at the same time alleviates the stress that acts on the connection between the protrusion and the main hull when the ship turns. The purpose of the present invention is to provide a hull resistance reduction device that enables the following.

For this reason, the hull resistance reduction device of the present invention is equipped with a hull resistance reduction protrusion that protrudes rearward from the rear end of the main hull at the load waterline at the stern, and on the left and right near the connection between the protrusion and the main hull. , each is characterized by a horizontal plate that extends to the side below the water surface.

Hereinafter, a hull resistance reducing device as an embodiment of the present invention will be explained with reference to the drawings. FIG. 6 is a side view of the stern portion thereof, and FIG. 7 is a sectional view taken along the line ■-■ in FIG. In FIGS. 6 and 7, the same reference numerals as those already described indicate substantially similar parts.

Further, symbols 17a, 17b, and 17b indicate horizontal plates.

A protrusion 9 is fixedly provided so as to protrude rearward from the rear end 11 at the load waterline 10 of the main hull 1, and a part of the protrusion 9 is above the load waterline 10 and the other part is below it. Horizontal plates 17a are shown symmetrically on the left and right in the vicinity of the connection between the main hull 1 and the protrusion 9, and extend over two levels, one above the other.

17b, 17b are provided, and the lower horizontal plate 17b
, 17b are arranged below the water surface.

The horizontal plates 17b and 17b provided below the water surface greatly reduce the turbulence of the water flow (see numerals 16a and 16b in Figs. 4 and 5) that occurs near the connection between the main hull 1 and the protrusion 9. Therefore, the increase in hull resistance due to the turbulence of this water flow can be reduced.

Moreover, such horizontal plates 17a, 17b, 17b
By providing the horizontal plates 17a, 17b, 17b', when the ship turns, the horizontal plates 17a, 17b, 17b' can receive the lateral force generated based on the water flow 14 acting on the protrusion 9. This prevents excessive stress from occurring at the connection between the hull 1 and the protrusion 9 and damaging this portion.

In the case where the projecting object 9 is hit by waves from the lateral direction and an impact force is applied, the horizontal plate 17a is moved in the same manner.

17b, 17b, so there is no possibility that excessive stress will be generated in the connection portion and cause damage to this portion.

As described in detail above, the hull resistance reducing device of the present invention is provided with a hull resistance reducing protrusion that protrudes rearward from the rear end of the main hull at the load waterline at the stern, and that the protrusion and the main hull are connected. It has an extremely simple structure, with horizontal plates protruding to the sides below the water surface on both the left and right near the connection points.In addition to the effect of reducing hull resistance due to the above protruding objects as wave-dissipating objects, This reduces the turbulence of the water flow near the joint, resulting in a reduction in resistance, and is also extremely advantageous in terms of the strength of the connection.

[Brief explanation of the drawing]

Figure 1 is a stern side view showing a conventional hull resistance reduction device, Figure 2 is a horizontal sectional view taken along the line ■-■ in Figure 1, and Figure 3 shows the turning state of a ship equipped with a hull resistance reduction device. FIG. 4 is an enlarged side view showing the vicinity of the stern end of the vessel;
Figure 5 is a cross-sectional view along the line ■■ in Figure 4, and
The figures show a hull resistance reducing device as an embodiment of the present invention, with FIG. 6 being a side view of the stern portion thereof, and FIG. 7 being a sectional view taken along the line -■ in FIG. 6. 1... Main hull, 2... Rudder, 3... Propeller, 4...
... Stern bossing, 5° propeller shaft, 6... Propeller cap, γ... Upper rudder support member, 8... Rudder handle, 9... Projection (wave-dissipating object), 9a, 9a. ... Outer plate of the protrusion, 9b, 9b... Auxiliary member of the protrusion, 10
... Loaded waterline, 10a... Any waterline, 11.
...Aft end of main hull above load waterline, 11'...
The rear end of the main hull under the water surface, 12...Hull center line,
13... Ship's turning trajectory, 14... Water flow at the stern, 15
a... Dobe stun frame, 15b-゛° lower stun frame, 16a. 16b--Disturbance of water flow, 17a, 17b, 17b-
horizontal board.

Claims (1)

[Scope of utility model registration request] At the stern, there is a protrusion for reducing hull resistance that protrudes backward from the aft end of the main hull at the load waterline, and on the left and right near the connection between the protrusion and the main hull, there are horizontal protrusions that protrude to the sides below the water surface. A hull resistance reduction device characterized by being provided with a plate.